the two that keep fighting... are they young males that haven't been neutered?
if so... it might be possible they are having a territorial conflict with one another?!
the little one looks slightly malnourished... possibly parasites... or is the young one getting bullied by the others maybe?
hard to tell what's up without more details.
it would probably be best if you try to contact some other vets in your area...
ps: !CATtip 100 CAT
I contact a vet and he told me that he will come sunday...thank you for your concern,it means a lot...
that's good... a professional should be able to help you properly and asses the situation correctly!
your tip of 100 CAT towards @shilpita was sent successfully